The present invention relates to an improved configuration for liquid controlled disk braking devices and is applicable to winch brakes of petrol drills, well rigs and shaft hoists, and to brake and speed controls for hoists.
Mechanical band brakes have traditionally been used in the prior art for various applications including winch braking devices of petrol drills, well rigs, and shaft hoists. However, due to inherent design characteristics, such devices are frequently unable to provide adequate braking torque and have been plagued with problems of unreliability, unstable braking effects, heat emissions, and difficulty in operation, adjustment, and maintenance. Such limitations tend to detrimentally affect equipment life, efficiency and required operational time.
The object of the present invention is to provide a liquid controlled disk brake having the advantages of increased braking torque, braking stability, sensitivity and precision in control, quick operation, easy installation and maintenance. Also desired is a design in which automatic apparatus control may be more easily incorporated into the overall system by allowing braking to be effected by either introducing or removing fluid pressure to particular components of the apparatus.
In accordance with the present invention, a liquid controlled disk braking device comprises a brake disk, brake calipers and a caliper carrier. The brake disk is fixed to the roller of a main hoist, which forms a brake pair together with the brake calipers. The caliper carrier is arranged on a winch base to position each of the brake calipers with respect to the brake disk. The brake calipers include both operational or service calipers and emergency calipers, which vary in relative number according to the braking needs of the particular machine or application.
The service calipers are used to provide braking force when the brake disk is rotating. Each service caliper includes two brake blocks positioned on either side of the brake disk with sufficient clearance to permit the disk to rotate. An oil cylinder connected to both brake blocks forces the blocks against the disk when the cylinder is pressurized and restores clearance when pressure is removed.
The emergency calipers are used to provide braking force when the disk is parked or in an otherwise stationary position. Like the service calipers, each emergency caliper includes two brake blocks positioned on either side oft he brake disk and connected to an oil cylinder. However, unlike the service calipers, each emergency caliper""s oil cylinder is configured to force the blocks against the disk when the cylinder is non-pressurized and restores clearance only when pressure is restored to the cylinder, thereby providing additional safety braking in the event of a loss of oil pressure to the system.
Features of the current invention include the ability to easily vary the amount of available total braking force by merely adapting the total number of braking clamps according to the particular needs of an application. Also included is an ability to provide additional braking force in the event of lost pressure to the braking system.
While the preferred embodiment oft his invention utilizes oil as the pressurizing fluid for the cylinder of each operational and emergency caliper, it will be appreciated that the invention contemplates other pressurizing fluids as well. The invention also contemplates other number combinations of operational and emergency calipers according the need of each particular application.
Thus, the invention does not reside in any one of the features of the liquid controlled disk braking device which is disclosed above and in the Description of the Preferred Embodiments and claimed below. Rather, this invention is distinguished from the prior art by its particular combination of features of the liquid controlled disk braking device disclosed. Important features of this invention have been disclosed in the Detailed Description of the Preferred Embodiments of this invention which are shown and described below to illustrate the best mode contemplated to date of carrying out the invention.
Those skilled in the art will realize that this invention is capable of embodiments which are different from those shown, and the details of the structure of the braking device can be changed in various manners without departing from the scope of this invention. Accordingly, the drawings and description are to be regarded as illustrative in nature and are not to restrict the scope of this invention. Thus, the claims are to be regarded as including such equivalent liquid controlled braking devices as do not depart from the spirit and scope of this invention.